1. Field of the Invention
The present invention relates to a bearing mechanism, and more specifically to a bearing mechanism for use in a motor.
2. Description of the Related Art
Conventionally, a motor provided with a fluidic dynamic-pressure bearing mechanism has been used as a motor for a disk drive apparatus. For example, in a spindle motor disclosed in FIG. 1 of Japanese Patent Application Publication No. 2009-136143, a bottom plate 10, a first bearing component 16, a second bearing component 18n and a fixed shaft 12 define a fixed component unit. Fluidic dynamic-pressure radial bearing units 22a and 22b are arranged between the fixed shaft 12 and a rotor component 14. A fluidic dynamic-pressure thrust bearing unit 26 is arranged between the first bearing component 16 and the rotor component 14. A pumping seal 36 is arranged between the second bearing component 18 and the rotor component 14. The rotor component 14 is provided with a circulation path 28. The circulation path 28 interconnects a radial outer region of the thrust bearing unit 26 and a radial inner region of the pumping seal 36. A seal gap 34 is provided at the radial outer side of the thrust bearing unit 26.
In a case where a shaft is fixed, as in the spindle motor disclosed in Japanese Patent Application Publication No. 2009-136143, the upper side of a lower seal gap is covered with a rotor. This makes it impossible to fill a lubricant from the lower seal gap. However, if a lubricant is filled from an upper seal gap, the infiltration of the lubricant is stopped in an opening of a communication path. This may make it impossible to introduce the lubricant to the lower seal gap.
Accordingly, a demand has existed for a bearing mechanism that makes it possible to easily fill a lubricant into the bearing mechanism from an upper seal gap.